U.S. patent application number 14/004536 was filed with the patent office on 2014-01-09 for camshaft adjuster.
This patent application is currently assigned to Schaeffler Technologies AG & Co. KG. The applicant listed for this patent is Andreas Strauss. Invention is credited to Andreas Strauss.
Application Number | 20140007827 14/004536 |
Document ID | / |
Family ID | 45755359 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140007827 |
Kind Code |
A1 |
Strauss; Andreas |
January 9, 2014 |
CAMSHAFT ADJUSTER
Abstract
An arrangement of a camshaft phaser (1) which has a drive
element (2) and at least two driven elements (3, 4), whereby the
camshaft phaser (1) has a first control valve (7) arranged
concentrically to the camshaft phaser (1), and a second control
valve (8) arranged off-centered with respect to the rotational axis
(5) of the camshaft phaser (1).
Inventors: |
Strauss; Andreas;
(Forchheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Strauss; Andreas |
Forchheim |
|
DE |
|
|
Assignee: |
Schaeffler Technologies AG &
Co. KG
Herzogenaurach
DE
|
Family ID: |
45755359 |
Appl. No.: |
14/004536 |
Filed: |
February 23, 2012 |
PCT Filed: |
February 23, 2012 |
PCT NO: |
PCT/EP2012/053095 |
371 Date: |
September 11, 2013 |
Current U.S.
Class: |
123/90.15 |
Current CPC
Class: |
F01L 2001/34469
20130101; F01L 1/344 20130101; F01L 2001/34456 20130101; F01L
2001/34493 20130101; F01L 1/3442 20130101; F01L 2001/34466
20130101; F01L 2001/0473 20130101 |
Class at
Publication: |
123/90.15 |
International
Class: |
F01L 1/344 20060101
F01L001/344 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 4, 2011 |
DE |
10 2011 006 691.8 |
Claims
1-7. (canceled)
8. A camshaft phaser comprising: a drive element; a first driven
element; a second driven element, each of the drive, first driven
and second driven elements arranged coaxially to a rotational axis
of the camshaft phaser; the first and second driven elements and
the drive element having several radially oriented vanes, the vanes
forming several working chambers finable with a hydraulic medium
under pressure so that a relative rotation is possible between the
drive element and one of the first and second driven elements as
well as between the first and second driven elements themselves; a
first control valve arranged coaxially to the rotational axis; and
a second control valve arranged off-centered with respect to the
rotational axis, the first and second control valves for regulating
pressurization of the working chambers.
9. The camshaft phaser as recited in claim 8 wherein the first
control valve regulates a first relative rotation between the drive
element and the first driven element, while the second control
valve regulates a second relative rotation between the drive
element and the second driven element.
10. The camshaft phaser as recited in claim 8 wherein the first
control valve is a central valve and is arranged in a hub of the
camshaft phaser.
11. The camshaft phaser as recited in claim 10 further comprising a
central magnet for actuating the central valve.
12. The camshaft phaser as recited in claim 8 wherein the second
control valve is a cartridge valve.
13. The camshaft phaser as recited in claim 8 wherein the first
driven element is connectable to a first camshaft, while the second
driven element is connectable to a second camshaft.
14. A camshaft system comprising a first camshaft, a second
camshaft and the camshaft phaser as recited in claim 8, the first
driven element connectable to the first camshaft, the second driven
element connectable to the second camshaft, and when the working
chambers are filled with a hydraulic medium under pressure, a
relative rotation occurs of both the first and second driven
elements with respect to each other and thus also of the first and
second camshafts with respect to each other, as well as another
relative rotation of the first and second driven elements with
respect to the drive element.
Description
[0001] The invention relates to a camshaft phaser.
BACKGROUND
[0002] Camshaft phasers are used in internal combustion engines in
order to vary the timing of the combustion chamber valves. Adapting
the timing to the current load lowers fuel consumption and reduces
emissions. A commonly employed model is the vane-type adjuster.
Vane-type adjusters have a stator, a rotor and a driving gear. The
rotor is usually non-rotatably joined to the camshaft. The stator
and the driving gear are likewise joined to each other, whereby the
rotor is situated coaxially to the stator as well as inside the
stator. The rotor and the stator have radial vanes that form oil
chambers which counteract each other, which can be filled with oil
under pressure and which allow a relative movement between the
stator and the rotor. Moreover, the vane-type adjusters have
various sealing lids. The assembly comprising the stator, driving
gear and sealing lid is secured by means of several screwed
connections.
[0003] U.S. Pat. Appln. No. 2009/0173297 A1 discloses a hydraulic
camshaft phasing device that has a driving gear and, coaxially
thereto, a stator with two rotors arranged concentrically to the
stator. Here, the stator can be configured so as to consist of a
single part or else of several components. The rotors and the
stator have radially oriented vanes. In this manner, the stator,
together with the rotors, forms working chambers that can be filled
with a hydraulic medium under pressure, so that a relative rotation
occurs between the appertaining rotor and the stator around the
rotational axis of the camshaft phaser. A partition wall that is
arranged between the rotors as a component of the stator axially
separates the rotors from each other. Each rotor can be connected
to a camshaft. In this case, the camshaft is configured as a hollow
shaft, whereas the other camshaft is made of solid material. Both
camshafts are arranged concentrically with respect to each other.
The cams that are associated with the camshafts are connected to
their camshaft in such a way that a relative circumferential
rotation of the cams or of the appertaining camshafts can occur
relative to each other, so that the timing of the inlet and outlet
valves associated with the cams can be adjusted continuously and
variably.
[0004] Such camshaft systems are already known and they comprise an
outer hollow shaft with cams that are non-rotatably connected
thereto, or for the inlet valves, and comprising an inner shaft
with cams likewise non-rotatably connected thereto, or for the
outlet valves, whereby these cams are connected to the inner shaft
via a pin connection. In order for the outer hollow shaft to be
able to rotate around the inner shaft, the pins are inserted into
associated slots in the outer hollow shaft. In this manner, the
cams of the outer shaft can be rotated with respect to the cams of
the inner shaft, and the valve stroke overlap can be regulated, and
the opening and closing timing relative to the piston position can
be adapted, whereby the piston, in turn, is connected via the
crankshaft to a belt and drive that is operationally connected to
the driving gear of the camshaft phaser.
SUMMARY OF THE INVENTION
[0005] It is an objective of the invention to provide a camshaft
phaser that has an especially compact design.
[0006] The present invention provides a camshaft phaser with two
control valves and yields a camshaft phaser or system whose
installation space is optimized and which entails less leakage. The
pressure loss that occurs due to long hydraulic paths and leakage
is reduced and an improvement of the responsiveness of the camshaft
phaser is achieved, at least by the first, centrally and coaxially
arranged control valve.
[0007] In one embodiment of the invention, the first control valve
is associated with the first driven element and it regulates the
relative rotation between this first driven element and the drive
element, while the second control valve regulates the relative
rotation between the second driven element and the drive element.
This unambiguous association has the advantage that, as a result of
the small distance to the first control valve, the first driven
element can be actuated extremely precisely.
[0008] In a detailed embodiment of the invention, the first control
valve is a central valve arranged in the hub of the camshaft
phaser. This reduces the installation space requirements and
increases the responsiveness of the camshaft phaser or of the
driven element associated with the central valve. A central valve
in the hub of the camshaft phaser comprises a control piston that
can be moved along the rotational axis of the camshaft phaser and
optionally a compression spring that sets the control piston in an
initial position. Due to the axial movement of the control piston,
openings leading from a feed line of a pressure-medium pump or from
a drain of the tank leading to the working chambers can be opened
or closed, thus ensuring the feed and drainage of hydraulic
medium.
[0009] In another embodiment of the invention, the central valve is
actuated by a central magnet, as a result of which the control
piston is moved coaxially to the rotational axis of the camshaft
phaser. The central magnet is arranged so as to be rigidly attached
to the housing or to a lid, but also so as to be rotationally
uncoupled, that is to say, a rotational movement of the control
piston stemming from the camshaft phaser cannot be transmitted to
the central magnet. The lid and thus also the central magnet are
arranged on the end face, facing away from the camshaft.
[0010] Central valves are configured as multi-way valves which have
an inlet and an outlet, whereby the inlet or the outlet is
connected to the hydraulic-medium channels leading to the working
chambers in such a way that the flow of fluid can be permitted or
interrupted.
[0011] Optionally, the central valve can be arranged inside or
coaxially inside the inner camshaft. Advantageously, it is situated
at the end of the camshaft to which the camshaft phaser is also
attached.
[0012] Another embodiment of the invention provides that the second
control valve is a cartridge valve. The cartridge valve is arranged
on the cylinder head, off-centered with respect to the rotational
axis of the camshaft phaser. The freely selectable arrangement of
the cartridge valve in terms of its location and positioning
creates degrees of freedom in terms of ease of installation, space
optimization and functional positioning in the hydraulic system as
well as design options for the hydraulic-medium gallery in the
cylinder head or in a crankshaft housing.
[0013] Cartridge valves, also known as proportional valves,
comprise a hydraulic part and a control part permanently connected
thereto. The hydraulic part is located in the hydraulic-medium flow
of the hydraulic-medium channels and it opens and closes the flow
cross-sections in order to distribute the hydraulic medium from the
feed line of a pressure-medium pump or from a drain of the tank
among the desired hydraulic-medium channels leading to the
cartridge valves. Cartridge valves are likewise configured as
multi-way valves having several flow cross-sections. The flow
cross-sections are usually configured as openings in a sleeve.
Inside the sleeve, there is a control piston that likewise has
openings and/or ring grooves that open or close the
hydraulic-medium paths through the sleeve. The control part of the
cartridge valve is configured as a solenoid that, when energized,
moves the control piston, so that so that the control piston opens
or closes the flow cross-sections. For this purpose, the control
piston is moved against the force of a spring that brings the
control piston back to its original position when it is in the
non-energized state.
[0014] The first driven element is supplied by the first control
valve. Towards this end, pressure is conveyed by the
hydraulic-medium pump to the control valve through a hollow space
that is coaxial to the inner camshaft; at the control valve, the
pressure is conveyed to the desired working chambers via
hydraulic-medium channels of the first driven element.
[0015] On the one hand, the hydraulic-medium feed line for the
second driven element is implemented by a gallery of several radial
hydraulic-medium channels situated parallel to the rotational axis
of the camshaft phaser, said channels being arranged in the outer
camshaft. On the other hand, the second driven element also has
several hydraulic-medium channels having a radial and parallel
arrangement by means of which hydraulic medium is conveyed into the
appertaining working chambers. The hydraulic-medium channels of the
camshaft and of the driven element are opposite from each other so
as to be in fluid communication at the connection site between the
camshaft and the driven element.
[0016] As an alternative, the hydraulic-medium feed can be
implemented by creating hydraulic-medium channels in the driven
element that lead to the desired working chambers.
[0017] Optionally, non-return valves can be installed in the driven
elements, in the drive element, in the control valves or in the
hydraulic-medium channels.
[0018] The inventive arrangement of the control valves with the
camshaft phaser for purposes of adjusting two concentric shafts
makes it possible to optimally utilize the installation space
available, while also improving the responsiveness of the adjuster
or of the system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Embodiments of the invention are depicted in the
figures.
[0020] The following is shown:
[0021] FIG. 1 a camshaft phaser according to the invention, in a
longitudinal section along the rotational axis of the camshaft
phaser; and
[0022] FIG. 2 a camshaft phaser according to the invention, in a
cross-sectional view along the rotational axis of the camshaft
phaser.
DETAILED DESCRIPTION
[0023] FIG. 1 shows a camshaft phaser 1 according to the invention,
in a longitudinal section along the rotational axis 5 of the
camshaft phaser 1. The camshaft phaser 1 has a drive element 2, a
first driven element 3, a second driven element 4, sealing means 17
as well as several radially oriented vanes 6 of the drive element 2
and of the driven elements 3, 4. The hub 10 of the first driven
element--which at the same time is the hub of the camshaft phaser
1--is arranged non-rotatably and concentrically on an axial end of
a first camshaft 18. The first camshaft 18 has a concentric central
channel 13 through which the hydraulic medium can be fed under
pressure. The first control valve 7, which comprises a sleeve 15
and a control piston 14, is likewise arranged concentrically in the
central channel 13 in the vicinity of the hub 10. The control valve
7 is arranged axially rigidly with respect to the first camshaft.
The control piston 14 is arranged axially movably with respect to
the sleeve 15 and it can be spring-loaded in an axial direction
with respect to the sleeve 15 in order to remain in a resting
position when it is in its non-actuated state. The control piston
14 is actuated by means of a central magnet 11 that is arranged on
an end face on the side of the camshaft phaser 1 facing away from
the camshaft. The central magnet 11 actuates the control piston 14
in the axial direction by means of an actuating pin 20, thus moving
the control piston 14 relative to the sleeve 15. The sleeve 15 and
the control piston 14 are each provided with openings known from
the state of the art, said openings then being opened or closed
during an axial relative movement. The hydraulic medium is fed
through the central channel 13 along the rotational axis 5 into the
first control valve 7. Depending on the position of the control
piston 14 relative to the sleeve 15, this hydraulic medium is
distributed among the corresponding hydraulic-medium channels 12
and thus radially through the hub 10, said channels each opening up
into corresponding working chambers A, B.
[0024] The working chambers C, D are supplied by means of a second
control valve 8 that is configured here as a cartridge valve 9.
This second control valve 8 is not arranged concentrically to the
rotational axis 5, but rather, it can be attached as desired to a
receptacle in the engine. Via hydraulic-medium channels 16, the
hydraulic medium reaches the working chambers C, D of the second
driven element 4. The cartridge valve 9 comprises a hydraulic part
that is in communication with hydraulic-medium channels and that,
like the first control valve 7, can distribute hydraulic medium
from a pressure pump among the appertaining hydraulic-medium
channels. The actuation is carried out by means of a solenoid 21.
The hydraulic part of the cartridge valve 9 is likewise equipped
with a control piston whose mode of operation is familiar to the
person skilled in the art, so that it will not be elaborated upon
here.
[0025] The arrangement according to the invention makes it clear
that, in order to independently actuate the first driven element 3
and the second driven element 4, it is advantageous to arrange two
separate control valves in the installation space, so that direct
hydraulic-medium channels can be employed. The two control valves
can be supplied with hydraulic medium from the pressure pump either
via a single feed line or else separately from each other, and even
employing two different pressure pumps.
[0026] FIG. 2 shows a camshaft phaser 1 according to the invention,
in a cross-section perpendicular to the rotational axis 5 of the
camshaft phaser 1. This depiction clearly shows the formation of
the working chambers A, B, D, C by the driven elements 3 and 4 with
the drive element 2. Together with a vane pair of the drive element
2, each vane 6 of a driven element 3 or 4 forms two working
chambers A and B. Thus, together with the vanes 6 of the drive
element 2, the vane 6 of the driven element 3 defines the working
chambers A and B. In contrast, in a comparable manner, the driven
element 4, together with the drive element 2, forms the working
chambers C and D. The radial, outer ends of the vanes 6 of the
driven elements 3 and 4 have sealing means 17 that separate the
working chambers in an oil-tight manner. Moreover, at least between
a driven element 3 or 4 and the drive element 2, the camshaft
phaser 1 has a spring element 13 in the circumferential direction
12. Here, both driven elements 3 and 4 are tensioned with the drive
element 2 by means of a spring element 13.
[0027] Therefore, when the working chamber A or B is filled with
hydraulic medium, the driven element 3 can be rotated relative to
the drive element 2. Filling the working chambers C and D with
hydraulic medium causes a relative rotation between the driven
element 4 and the drive element 2.
LIST OF REFERENCE NUMERALS
[0028] 1 camshaft phaser [0029] 2 drive element [0030] 3 first
driven element [0031] 4 second driven element [0032] 5 rotational
axis [0033] 6 vanes [0034] 7 first control valve [0035] 8 second
control valve [0036] 9 cartridge valve [0037] 10 hub [0038] 11
central magnet [0039] 12 hydraulic-medium channel [0040] 13 central
channel [0041] 14 control piston [0042] 15 sleeve [0043] 16
hydraulic-medium channel [0044] 17 sealing means [0045] 18 first
camshaft [0046] 19 second camshaft [0047] 20 actuating pin [0048]
21 solenoid [0049] A working chamber [0050] B working chamber
[0051] C working chamber [0052] D working chamber
* * * * *